The present invention relates to a semiconductor device, and can be preferably used in a semiconductor device using, for example, a nitride semiconductor.
In recent years, semiconductor devices using a group III-V compound having a larger bandgap than silicon (Si), for example, gallium nitride (GaN), are drawing attention. A semiconductor element has a p-type impurity region and an n-type impurity region. For example, an n-type MISFET has a source region and a drain region, each including an n-type impurity region, on both sides of a p-type impurity region that will serve as a channel region. The n-type MISFET has a constituent part (npn constituent part) including such an npn-type impurity region.
When a Si substrate is used, such an n-type or p-type impurity region can be easily formed by an ion implantation process. However, it is difficult to form a p-type impurity region over a GaN substrate or in a GaN layer epitaxially grown by an ion implantation process.
Accordingly, for example, in Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2011-210780), an npn constituent part is formed by growing a p-GaN layer while being doped with p-type impurities by a metal organic chemical vapor deposition process or a molecular beam crystal growth process and then by implanting Si ions into the p-GaN layer to form an n+-GaN region.